Of course, there are previously known valve devices for such an operation. However, such devices are all dependent on a resilient material for providing a seal, a liquid tight seal, between a nozzle or corresponding element and the end of the reciprocating armature that controls the output.
Said resilient material is arranged as a thick layer onto the plate shaped element where nozzles or corresponding passages are formed. By bringing the end of the armature in abutment against the resilient layer around the nozzles, the prior art technique provides a liquid tight "joint" between the armature and the nozzle.
However, defects indicate that said known layers of a resilient material do not resist long term strain in a sufficient degree meaning that cracks are formed, the material expands or shrinks. The influence of the actual type of ink is also substantial which is very clearly noticeable. Furtheron, there is a need for shifting between different ink types, for instance solvent based, generally alcohol based inks and water based inks. In order to do this, however, there is needed a cumbersome and very time consuming conditioning of the resilient layers.
The object of the present invention is to eliminate said drawback and offer a more advantageous alternative. A further object is to provide an efficient seal between the armature valve head and an output plate, without the need for an exact and time consuming adjustment operation.